At present, an image encoding process is: An encoder side obtains an encoded image and prediction information of the encoded image, so as to obtain a residual of the encoded image; and on a decoder side, the decoder side performs according to the prediction information and the residual of the image, decoding to obtain an image that is before encoding.
At present, a 3D encoding and decoding technology includes multiple encoding and decoding technologies, for example: a recursive quadtree encoding (RQT) technology. In 3D encoding/decoding, to reflect depth information of an image, a depth map needs to be encoded/decoded. Therefore, compared with conventional texture encoding/decoding, an image block segmentation method for a depth modeling mode (DMM) is added. The DMM includes two modes: a DMM1 mode, and a DMM4 mode. In the DMM1 (Depth modeling mode 1), an image block is segmented in a wedge manner, and in the DMM4 (Depth modeling mode 4), prediction segmentation is performed according to a corresponding texture reference block.
A DMM technology may be implemented in combination with an RQT technology. According to characteristics of a depth map, in a process of applying an DMM to an RQT, the DMM may be implemented by using four modes, and the four modes may be marked with numbers. In this way, during encoding/decoding of a depth map block, the four modes need to be detected, and during decoding, two modes need to be detected as well, causing high encoding/decoding complexity, and low encoding/decoding efficiency.